One of the more common afflictions to affect aging eyes are cataracts, which cause gradually deteriorating vision. Advances in ophthalmic surgery allow many cataracts to be removed and vision restored.
Treating cataracts typically involves the removal of the clouded natural lens and replacement with an artificial lens. Removal of the lens requires an incision or tunnel to be made in and/or adjacent to the cornea. The tip portion of a phaco emulsifier is inserted through the incision and vibrates ultrasonically to liquefy the lens. The emulsified lens is removed from the lens capsule by aspiration. Modern aspirators also perform irrigation. I/A instruments have dual passages, one for irrigation and the other for aspiration. Usually the passages are coaxial, the inner passage being formed by a rigid or semi-rigid cannula, and the outer passage having a distal portion formed by a sleeve which may be resilient. One or more components of the tips are removable from the handpiece of the instrument for selection of an appropriate or desired tip, and for replacement of the tip.